One of the best things that the bishops of the American Catholic Church did during the great wave of sex abuse revelations 16 years ago — and yes, there's a low bar for "best" — was to establish a National Review Board, staffed by prominent laymen, with the authority to commission an independent report on what exactly had happened in the church.

The result was a careful analysis by the John Jay College of Criminal Justice that detailed the patterns of priestly sex abuse in American Catholicism between 1950 and 2002. Then attached to that data was a larger discussion from the review board's members, which managed to be reasonably evenhanded about subjects (priestly celibacy and homosexuality, above all) that lend themselves to culture-war hysteria both inside and outside the church. Thanks to the members' labors, any journalist or historian interested in assessing the problem of priestly sex abuse dispassionately, and anyone seeking the truth about a lurid and polarizing story, can turn to a sober and detailed accounting.

Now, unfortunately, it needs to happen again. But what needs to be commissioned this time, by Pope Francis himself if the American bishops can't or won't, is an inquest, a special prosecutor — you can even call it an inquisition if you want — into the very specific question of who knew what and when about the crimes of Cardinal Theodore McCarrick, and why exactly they were silent.

Here are the allegations against McCarrick as we have them right now. In 1971, as a young priest, the future cardinal sexually assaulted a 16-year-old altar boy — the crime that almost 50 years later finally led to his public exposure as a pederast. Around the same time, he groomed and molested a teenage boy who had been the first child he ever baptized.

What happened to that young man happened to numerous seminarians and young priests as Father McCarrick became Bishop and then Archbishop McCarrick. The first written accusation (that we know of) was filed by one of his priests in 1994, addressed to McCarrick's successor as the Bishop of Metuchen; the priest who complained was transferred to another diocese while his abuser's rise continued.

By the end of that decade, McCarrick's sexual misbehavior (if perhaps not its full scope) was known by enough people that a group of American laypeople went to Rome to petition against his appointment as archbishop of Washington, D.C., and at least one New York priest, Boniface Ramsey, sent a letter to the Vatican offering a similar warning.

These petitions were in vain; McCarrick became Washington's archbishop and then a cardinal. At this point the sex abuse scandal broke in Boston, and elsewhere — and the Washington archbishop became the avuncular, reassuring media point person for his fellow bishops, issuing statements of concern and condemnation that if he really feared the punishments of hell would have turned to ashes in his mouth.

Then in 2005 and again in 2007, two New Jersey dioceses settled privately with two men alleging abuse or harassment at McCarrick's hands. This presumably expanded substantially the number of people who knew about his crimes. Yet nothing was said publicly by the church about these settlements. Ramsey continued to direct petitions to his superiors, including both the late Cardinal Egan of New York (a figure of dubious reputation around sex abuse) and the cardinal archbishop of Boston, Sean O'Malley (whose record and reputation are much stronger), to no visible effect.

In 2013, when Pope Benedict XVI resigned, McCarrick was too old to vote in the conclave but was active in the politicking. When Pope Francis was elected, he became an eminence grise, whose lobbying helped elevate several of the new pope's choices for high office in the American church — including the new cardinal archbishop of Newark, Joseph Tobin, and the head of the Vatican dicastery for family life, Kevin Farrell, formerly bishop of Dallas, both of whom considered McCarrick a mentor.

I think this long and sickening narrative should clarify why the McCarrick case, though "only" about one abuser, merits an expansive and public accounting of the facts. Over the course of multiple decades, across a period in which not just crimes but cover-ups devastated the moral credibility of the church's hierarchy, many important figures in Rome and the United States must have known that a man who embodied the official response to the scandal was as guilty as any of the priests whose conduct he pretended to deplore.

Someone, or indeed many someones, needs to be held accountable for this disaster. And that accountability requires more than self-exculpating statements from the cardinals involved. It requires judgment, which requires more certain knowledge, which requires investigation, which probably requires an investigator with a mandate from the pope himself.

There are a few American bishops still with media platforms, a few with intellectual chops. But many of the notional leaders of the church are important only within the bureaucracies they manage and as invisible to the average churchgoer as a Target regional vice president would be to the average weekend shopper at the superstore. Thus the great irony of the McCarrick moment — that the kind of crimes once covered up because of the power and influence of bishops might now be swept under quickly because of the episcopacy's obscurity and irrelevance.

The question that the church's leaders need to ask themselves, in America but especially in Rome, is whether they are happy with this settlement — happy to be ignored so long as they can also evade accountability for what's still rotten in the church, happy to serve out their time as stewards of a declining institution rather than demanding the heads of the men whose culpable ignorance made the decline much steeper than it should have been.